Working Memory
We have previously discussed in general terms the
frontal con-tribution to memory at the level of encoding and retrieving.
However, memory researchers believe that the frontal lobes modulate the use of
memory in executive functions such as planning and decision-making. This kind
of memory is referred to as “working memory” (Miller et al., 1960). In their recent comprehensive review of working
memory models, Miyake and Shah (1999) proposed that working memory “is those
mecha-nisms or processes that are involved in the service of complex cognition,
including novel as well as familiar, skilled tasks”. This definition
differentiates working memory from short-term memory because it suggests that
working memory goes beyond simply keeping information “in mind”; rather,
working memory brings or keeps information online in a goal-directed fashion.
Baddeley and Hitch (1974) were the first to provide a human cognitive model for
the concept of working memory, and the neuroanatomical localization of this to
the frontal lobes has been largely advanced by the extensive work of
Goldman-Rakic and colleagues (Goldman-Rakic, 1987, 1988; Baddeley and Hitch,
1974).
Figure 15.8 illustrates the major components of the
Badde-ley and Hitch model of working memory. This model (Baddeley and Hitch,
1974) provides for a dynamic system of temporary and limited storage. It is
composed of a central executive and two “slave” systems, a visual–spatial
sketchpad, and a phonological loop.
The central executive aspect of the working memory
sys-tem appears to exert control over the flow of activity between the slave
systems and provides the input to long-term memory. However, this is also the
least well-understood component of working memory. The interaction of slave systems
with the central executive probably reflects the interplay between the frontal
lobe mechanisms of executive control of input received from parietal, temporal
and occipital systems of perception and association. Although the detailed role
of the central executive remains unclear, evidence from the animal and human
experi-mental literature suggests that the prefrontal cortex is specialized
with respect to working memory.
The prefrontal cortex may be a kind of multipurpose
working memory center, with each area concerned with a different domain. The
prefrontal cortex would then function as the coordinating el-ement in a
parallel distributed cortical–cortical network
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.